mp-yaml: A simple parser of YAML for MicroPython

This is a simple parser of a subset of the YAML grammar for MicroPython, suitable for reading YAML configuration files.

Features

• nested dictionaries with consistent indentation (4 spaces)
• scalars: strings, integers, floats, booleans, and nulls
• flat lists of scalar values
• inline comments (after values, using '#')
• automatic type conversion for scalars
• pretty-printing in either JSON or YAML format

Any features beyond those listed above, e.g., nested lists, multiline strings, anchors, complex keys, inline dictionaries and complex YAML syntax are not supported.

Sample Usage

Here's a sample usage using the ConfigLoader:

from config_loader import ConfigLoader

config = ConfigLoader.configure()
value = config["kros"]["motor"]["pid_controller"]["kp"]

Requirements

No external dependencies. This will run in both MicroPython and CPython.

Installation

Copy the files as needed to your MicroPython device, altering the path if necessary (e.g., you may wish to keep them in a lib directory).

Files

• yaml.py: The YAML parser
• pprint.py: Pretty-print YAML or JSON
• stringbuilder.py: similar to Java's StringBuilder
• config_loader.py: A convenient application configuration loader
• test.py: test file
• config.yaml: sample YAML file used for test

Status

This is a first release and supports the features as described, but it has not been extensively tested.

Support & Liability

This project comes with no promise of support or acceptance of liability. Use at your own risk.

Copyright & License

All contents Copyright 2020-2025 by Murray Altheim. All rights reserved.

Software and documentation are distributed under the MIT License, see LICENSE file included with project.